1. Field of the Invention
This invention relates to a cooling system for an electronic apparatus having heat generating components, and more particularly to a self-contained portable cryogenic cooling system removably secured in an Electronic Industry Association (EIA) enclosure which will provide cryogenic cooling to electronic components in the EIA enclosure.
2. The Prior Art
Cryogenic cooling of CMOS (Complimentary Metal Oxide Semiconductor) chips has the potential for being the single largest market for cryocoolers. CMOS chips are used in the CPU (Central Processing Unit) of computers and are currently air cooled and operate at temperatures as high as 358.degree. K. (185.degree. F.). The computer manufacturers have found that by operating the CPU of a CMOS computer at cryogenic temperatures (77.degree. K., -321.degree. F.), the operating speed of the computer can be increased by up to a factor of two. The increase in speed effected by cryogenic cooling is comparable to that obtained by doubling the number of CPU boards in the computer. Particularly in machines with more than one board, cryogenic cooling can be a less costly way to double the speed of the computer.
Further, in the Prior Art, systems for cooling logic units by conduction with a liquid and/or at cryogenic temperature have been developed. In liquid cooling systems, logic units are completely immersed in a liquid bath. Typically, the cooling system is provided with liquid nitrogen. In a liquid cooling arrangement, components such as pumps, liquid storage vessels, and piping are located external to the enclosure which houses the logic units, otherwise major computer cabinet redesigns are necessary. In cryogenic cooling systems, which typically use liquid nitrogen and are of the "split" type, the logic units are placed in a special cryostat enclosure and the cryocooler, separated from the cryostat, is in another special enclosure, or the logic unit and cryogenic cooling system are mounted in a special cabinet with the electrical output of the logic unit connected to the computer processors in the standard EIA enclosure by way of electrical cables. The separate enclosures were needed because of the large size of the systems and to separate the noise and vibration of the cooling system from the logic unit.